The rear of the tenders were shimmed to allow the tank to sit more level upgrade.
This can almost always be accomplished in model form by simply adding a single brass washer between the rear truck and bolster plate. The only time I have ever had to remove a bolster plate to get the correct look on a model was on a K-37, which in my opinion is the one which shows the most slope because of the shorter wheelbase.
A couple of years ago there was a long discussion about this, and Woody Woodward informed us that one of the 490 tenders, I recall the 492, actually sloped to the rear under a heavy load of water. This one is the only one that can actually be attributed to soft or broken springs on the D&RGW Narrow Gauge, as water weighs far more than coal. An empty tender sits exactly the same as a loaded tender. This was done intentionally.
All locomotive trim was always silver on the D&RGW in the later years, with the apparent exception of engines in Montrose. The D&S and C&TS have followed this practice with silver trim only.